50/50, you can use a really low weight and make the muscles feel tension if you do a movement slow enough but the tension won't be anywhere near enough to affect muscle growth, it will just fatigue the muscle in question more than likely through lactic acid build-up; using a moderate to heavy weight may work with tension added to the mix but it still ends up being a significant load, so the muscle does respond to load and not just tension.

Dynamic tension was all the rage, several decades ago, but it wouldn't have built any muscle (or any significant mass), it may have helped "tone" or solidify muscle that was already present due to the use of constant tension but it wouldn't have been enough to induce growth.